The National Program for Early Diagnosis (PNDC), better known as the heel prick test, has been underway since 1979 with the objective of diagnosing genetic diseases in infants where these may benefit from early treatment, so avoiding occurrences including mental retardation, irreversible serious illness and even death.

With the development of the programme, which currently covers 26 diseases, 25 of them of genetic origin, "public health gains" have been maximised, the head of the neonatal screening, metabolism and genetics unit of the Ricardo Jorge National Health Institute (INSA), Laura Vilarinho, said in an interview with Lusa.

The test should be carried out between the third and sixth day after birth, and consists of the collection of blood droplets by pricking the baby's foot.

Although the test is not mandatory, the PNDC currently has a coverage rate of 99.5%, with the mean time of treatment for diseases diagnosed starting of 9.9 days. At the beginning, the coverage was 6.4% and treatment started on average at 28.5 days.

Since the start of the programme and until the end of 2018, a total of 3,803,068 children have been screened. As a result 2,132 cases of disease have been diagnosed, 779 of them involving metabolic diseases, 1,304 of congenital hypothyroidism and 49 of cystic fibrosis, said Vilarinho, who has been involved in programme from the start.

The programme took off in Portugal in 1979 with the screening for phenylketonuria, which has a prevalence in Portugal of one case for each 10,867 births. Two years later it began to include congenital hyperthyroidism, with a prevalence in the country of one case per 2,892 births.

"For many years it was only these two screenings that were in the programme,” noted Vilarinho, adding that it was extended to 13 metabolic pathologies in 2004. In that year, equipment was acquired that enabled the simultaneous screening for these diseases.

A year later, screening was extended to 17 diseases and so on, until in 2008 there were a total of 24 metabolic diseases being screened for – now up to 26, with more on the way.

"Rare diseases are mostly genetic diseases and for most of them there is no treatment, but when there is a treatment that is effective ... and patients are without neurological alterations" these diseases are candidates to be included in the test, stressed Vilarinho.

She attributes the success of the test to parents, who have "cherished” the programme, and to nurses who collect the blood samples in health centres and hospitals in "a very, very special way". For the treatment to start on average at ten days of the baby's life, she stressed, "everything has to be done in a very streamlined way, the whole system has to work perfectly.”